How can X, Y, Z and W go above one in a quaternion animation on Blender?
But....Blender does work with quaternions between 0 and 1. 

There's an interesting video put out by Nathan Vegdahl (that's part of his Humane Rigging series) that discusses quaternions: https://www.youtube.com/watch?v=FRD0PgsY3pU&amp;index=14&amp;list=PLE211C8C41F1AFBAB
If you go to about 10:31 in the video, it talks about quaternions only being valid between 0 and 1. By 11:09, he mentions what Blender does with values greater than 1. 

Not sure what would prevent the file from being imported correctly.